[July 27, 2009]WASHINGTON (AP) -- A year after government scientist Bruce Ivins killed himself while under investigation for the lethal anthrax letters of 2001, the Justice Department is on the verge of closing the long, costly and vexing case.

Several law enforcement officials told The Associated Press that the department had tentatively planned last week to close the case, but backed away from that decision after government lawyers said they needed more time to review the evidence and determine what further information can be made public without compromising grand jury secrecy or privacy laws.

Officials told the AP the decision to close the case has been put off for what may be weeks, as the FBI and Justice Department continue to wrestle with an investigation that has led many to question the quality of their work and the certainty of their conclusions.

The officials spoke on condition of anonymity because they were not authorized to discuss internal deliberations about the case.

Justice Department spokesman Dean Boyd declined to comment on the discussions but said the agency and the FBI continue working to conclude the investigation. "We anticipate closing the case in the near future," Boyd added.

The anthrax letters were sent to lawmakers and news organizations as the nation reeled in the weeks after the Sept. 11, 2001, terror attacks.

With childish, blocky handwriting and chilling scientific expertise, the letters spread death through the mail.

The spores killed five people: Two Washington, D.C., postal workers, a New York City hospital worker, a Florida photo editor and a 94-year-old Connecticut woman who had no known contact with any of the poisoned letters. Seventeen other people were sickened.

For years, the FBI chased leads. Authorities tried to build a case against biowarfare expert Steven Hatfill, but ultimately had to pay him a multimillion-dollar settlement.

Then, last year, they announced that the mystery had been solved, but the suspect was dead. Authorities said in the days before the mailings, Ivins had logged unusual hours alone in his lab at the Army Medical Research Institute of Infectious Diseases at Fort Detrick, Md. They also say he threw investigators off his trail by supplying false leads as he ostensibly tried to help them find the killer.

As the FBI closed in on Ivins last summer, the 62-year-old microbiologist took a fatal overdose of Tylenol, dying on July 29, 2008. After Ivins' suicide, FBI Director Robert Mueller said the investigation found Ivins was the culprit, and prosecutors said they were confident he acted alone. Officials insisted they were on the verge of indicting him and could have convicted him.

Skeptics -- including prominent lawmakers -- pointed to the bureau's long, misguided pursuit of Hatfill, and noted there was no evidence suggesting Ivins was ever in New Jersey when the letters were mailed there.

This week, the National Academy of Sciences is set to begin a formal review of the FBI's scientific methods in tracing the particular strain of anthrax used in the mailings to samples Ivins had at his Fort Detrick lab.

Closing the case, even if some new details are released, seems unlikely to do much to sway those like Rep. Rush Holt, whose New Jersey district is home to some of the stricken postal workers.

"Most people affected -- the families, the post office workers -- will not feel there's closure in this case, and the people of New Jersey will not be able to be confident that there isn't still a murderer in their midst," said Holt.

Holt said the FBI built an "entirely circumstantial" case against Ivins.

"I watched as they went off on wild goose chases and then conveniently have a suspect who isn't around to defend himself," the New Jersey Democrat said. "Dr. Ivins was an oddball, no question, but you don't build a case on that."

In preparation for an announcement prosecutors had decided to close the "Amerithrax" case, investigators wrote a 110-page summary of their work, laying out the timeline of events over the past eight years, according to the officials speaking on condition of anonymity.

That 110-page review was pared down to about 40 pages, and then a still-shorter version. Now it's unclear if any of those documents will be released.

Senate Judiciary Chairman Patrick Leahy, D-Vt., who was the target of one of the letters, has said he does not believe Ivins acted alone.

Ivins' lawyer, Paul Kemp, has long maintained that the scientist was innocent and would have been cleared at any trial. Some of Ivins' colleagues also doubt the FBI's conclusions.

Plenty of questions remain unanswered, whenever they close the investigation, Kemp said.

"The case continues to remain an open sore with no conclusive evidence, and it is still devastating to (Ivins') family," said Kemp.